Stuck in High Hrothgar ('use your unrelenting force shout')?

Okay, so I'm in High Hrothgar, at the part where I'm with the 4 Graybeards and they are like 'use your unrelenting force shout to strike the targets when they appear'.I have been stuck here for like 4 hours.Guy walks up, screams, and the blue orb appears, I shout at it, next guy does it, I shout at it, next guy does it, I shout at it.Nothing happens, nothing ever happens. The one guy just keeps saying 'use your unrelenting force shout' and the cycle just repeats OVER AND OVER and I don't know what to do. TWICE in all the times ive done it, I see this etheral (?) guy come out of the orb, but then he disappears like half a second later.How the heck do I get past this part?